Chemically modified field effect transistor (CHEMFET)-based sensor technologies have been studied as they have potential as microsensors for food, biomedical and environmental analytics. CHEMFETs have advantages over conventional ion-selective electrode-based sensors in terms of small dimensions, low-output impedance, fast response, mass-fabrication ability and great potential for integration into smart sensor arrays for detecting multi-analytes. However, present devices are mainly based on inorganic metal-oxide-semiconductor field effect transistors (MOSFETs). A limiting factor of such MOSFET devices is the relatively high manufacturing costs. This is particularly true for clinical applications which have strict safety requirements and where the use of disposable microsensors is highly desirable.
Biochips, including DNA and protein array-based devices, have become an important tool in the life sciences, biomedical applications and drug discovery, due to the many benefits of miniaturization, integration and high-throughput mode of operation. Existing biochip technology is based however on fluorescent-based glass or silicon array fabrication and can be very expensive. For more than a decade now, organic field effect transistors (OFETs) based on conjugated polymers, oligomers, or other organic molecules have been envisioned as a viable alternative to more traditional, mainstream thin-film transistors (TFTS) based on inorganic materials.
A major obstacle in the development of an addressable electronic array biochip is the occurrence of ionic shortage of different sensing arrayed electrodes because of the electrolytes in the sample. US 2002009064A1 discloses a high density addressable array biochip for electronic detection, which uses microchannels to separate different column arrays to eliminate the ionic shortage problem of addressed arrayed electrodes. The microfluidic method used however results in a much higher chip production cost and it is also very difficult to fabricate nano-array chips which require the nanoscale channels for eliminating the ionic shortage.
There thus remains a need to develop more efficient devices and methods to fabricate electrical or electrochemical array chips. Particularly, there remains a need in the art to develop low cost column-and-row addressable biochip arrays for the electrical or electrochemical detection of molecular interactions that can be easily and cost-effectively fabricated and that reduces the cost of performing various analyses, while increasing the effectiveness and utility thereof. More particularly, there remains a need in the art to develop electronic addressable biochips.